diff --git a/MIL/C07_Structures/S02_Algebraic_Structures.lean b/MIL/C07_Structures/S02_Algebraic_Structures.lean
index 813d75b..df9beec 100644
--- a/MIL/C07_Structures/S02_Algebraic_Structures.lean
+++ b/MIL/C07_Structures/S02_Algebraic_Structures.lean
@@ -321,7 +321,7 @@ SOLUTIONS: -/
   neg : α → α
   add_assoc : ∀ x y z : α, add (add x y) z = add x (add y z)
   add_zero : ∀ x : α, add x zero = x
-  zero_add : ∀ x : α, add x zero = x
+  zero_add : ∀ x : α, add zero x = x
   neg_add_cancel : ∀ x : α, add (neg x) x = zero
 
 -- BOTH: